Progestin shot experience

Jordz

So about 3 weeks ago I got my first birth control shot, doc said it was called progestin. It's my first time on birth control and my doc told me the side effects of this one are much less compared to the others, but I need to do it every 8 weeks. Anyone have experience with this brand of BC? I ask cause I'm 5 days late but with all the pre-period symptoms. Is it normal that the shot will mess up my cycle a bit?